Pathologist Dr. Joseph Cohen said more information was needed to determine why Clayton Lockett died. Oklahoma officials have said it appeared Lockett didn't receive a full dose of three lethal drugs, perhaps after a vein collapsed.

Cohen said Lockett had good veins. He said it appeared the execution team failed repeatedly while inserting an intravenous line.

After Lockett struggled, the execution team discovered a problem with the IV. Officials halted the execution, but Lockett died shortly afterward. Results from a state autopsy are pending. Toxicology reports haven't been issued, so it's unclear how much of the drugs Lockett received.

While you're here, peruse these breaking news photos from our U Local website. When YOU see breaking news happen, email your photos to ulocal@koco.com -- or post them (and your videos) to http://ulocal.koco.com.